In a magnetic disk device, a head stack assembly (HSA) performs reading/writing of magnetic record. The HSA comprises, for example, a carriage having a plurality of arms and a head gimbal assembly (HGA) joined to each arm. The HGA has a suspension joined to a leading end part of each arm, and a slider located at a leading end part of the suspension. A magnetic head (such as thin-film magnetic head) is embedded in the slider. A carriage (E-shaped carriage) having a plurality of arms may be referred to as an E-block.
In a related art, fitting and joining disclosed in Japanese Unexamined Patent Publication No. H5-303855 has been known as a method of joining an arm and a suspension. In the method disclosed in Japanese Unexamined Patent Publication No. H5-303855, a flange is formed on the suspension and a fitting hole is formed in the arm. A position of the flange and a position of the fitting hole are aligned and the flange of the suspension is fitted into the fitting hole of the arm. Then, a metal ball is introduced by a pressurization shaft from a hole of the flange and the metal ball goes through the each hole. A diameter of the metal ball is larger than the minimum diameter of the hole of the flange. Thus, the flange of the suspension is pushed and bent by the metal ball and the flange is pressed against the arm. That is, swaging (or caulking) is performed. With these procedures, the arm and the suspension are joined to each other.
In addition, a joining method other than fitting and joining is also known. For example, in Japanese Unexamined Patent Publication No. H7-178582, a method of joining a suspension and an arm by irradiation of a joining beam (by YAG laser) is disclosed.